No, the 1989 Exxon-Valdez spill doesn't make the list.

Gulf War, 1991

Gulf War, 1991

Location: KuwaitGallons: 240 to 336 million

How It Happened:
As Iraqi forces retreated from Kuwait during the first Gulf War, they opened the valves of oil wells and pipelines in a bid to slow the onslaught of American troops. The result was the largest oil spill history has seen. Some 240 million gallons of crude oil flowed into the Persian Gulf. The resulting oil slick spanned an area just larger than the size of the island of Hawaii.

The Cleanup:
Coalition forces managed to seal off some of the open pipelines using smart bombs, but most recovery efforts had to wait until after the war. At that point 25 miles of booms (orange ropelike products that contain the oil that is floating on top of the water) and 21 skimmers (machines that separate oil from water) were deployed in the gulf, mostly to protect the water intakes of desalinization, industry and power plants. Together with vacuum trucks, about 58.8 million gallons of oil was recovered from the gulf.

The largest oil spill the world has seen exacted little permanent damage on coral ecosystems and local fisheries, according to a report by the Intergovernmental Oceanographic Commission at Unesco. The study concluded that about half the oil evaporated, one-eighth of it was recovered and another quarter washed ashore, mostly in Saudi Arabia.

Ixtoc 1 Oil Well, 1979

Ixtoc 1 Oil Well, 1979

Location: Bay of Campeche, MexicoGallons: 140 million

How It Happened:
In June 1979, an oil well in the Bay of Campeche collapsed after a pressure buildup sparked an accidental explosion. Over the next 10 months about 140 million gallons of crude spouted into the Gulf of Mexico from the damaged oil well.

The Cleanup:
In order to slow down the flow of oil from the damaged well, mud and later steel, iron and lead balls were dropped down its shaft. According to PEMEX (Mexican Petroleum), half the oil burned when it reached the surface and a third evaporated. PEMEX also hired a company to spray dispersants over 1100 square miles of oil slick. Dispersants effectively act like dish soap, breaking up oil so that more of it can mix into the water. That way, they can reduce the effect of the oil slick on shorelines. On the Texas side of the gulf, skimmers and boomers were placed in the water to protect the bays and lagoons of the Barrier Islands.